1. Field of the Invention
This invention relates to dielectric recording media which are used in electrostatographic printing processes and to methods of making such media. In another aspect, it relates to dielectric resin coating compositions.
2. Description of the Prior Art
In electrostatographic printing processes an electrostatic charge pattern is applied to the recording medium directly or by a transfer technique and is developed by any of the conventional toning techniques to form a permanent visible image. The dielectric recording medium should accept an electrostatic charge rapidly and retain it sufficiently long for the charge pattern to be developed. A number of dielectric recording media have been described in the prior art.
Typical dielectric recording media comprise an electroconductive substrate and a coating of dielectric resin. While they have, in general, been adequate in their dielectric properties and electrostatic charge acceptance, they have been deficient in appearance and feel because the dielectric coatings present surfaces of high gloss and smoothness. Moreover, such surfaces are unsatisfactory because of lack of "tooth" or receptivity to marking by conventional means such as pencil, pen and ink, etc.
Incorporation of pigments into the dielectric coatings can overcome these deficiencies of appearance and lack of tooth but usually with a sacrifice in electrical properties. For example, clay pigments which are widely used in paper coatings, have been found to inhibit drastically the ability of a coating to accept and hold an electrostatic charge. Other common pigments exhibit similar unsatisfactory behavior.
Thus, there exists in the art a need for a dielectric recording medium comprising a dielectric coating containing a low-cost pigment and possessing adequate electrical and physical properties.